The present invention relates to an upper vehicle-body structure of a vehicle comprising a pair of right-and-left roof rails extending in a vehicle longitudinal direction at right-and-left both end portions of a roof portion of a vehicle body, a roof panel provided between the pair of right-and-left roof rails, a front header provided at a front portion of the roof panel and extending in a vehicle width direction, a pair of right-and-left front pillars joined to the roof rails at upper portions thereof and extending downward, and a windshield (front window) provided between the front header and the front pillars.
An upper vehicle-body structure of a vehicle comprising a roof panel which forms a roof portion of a vehicle body and a roof reinforcement which is provided below the roof panel to extend in the vehicle width direction is known as exemplified by the upper vehicle-body structures disclosed in Japanese Patent Laid-Open Publication Nos. 2014-58224 and 2002-248943.
The above-described first patent document discloses the upper vehicle-body structure of the vehicle, in which the roof reinforcement is formed in a W shape in the side view such that it has joint faces to be joined to a lower face of the roof panel at its longitudinal-both end portions and its longitudinal-central portion, and the other portion of the roof reinforcement than the above-described joint faces is spaced downward apart from the lower face of the roof panel, wherein this roof reinforcement is joined to the lower face of the roof panel. The structure of the above-described first patent document improves a tensional rigidity of the roof panel (see paragraphs [0038], [0049] of the above-described first patent document).
The above-described second patent document discloses a sunroof structure for a vehicle as an upper vehicle-body structure of the vehicle, in which first and second cross members as a roof reinforcement are arranged in an X shape in the plan view. The X-shaped first and second cross members increase a rigidity of the roof (see paragraph [0027] of the above-described second patent document).
The inventors of the present invention have conducted the researches for improving the comfortability of the ride, and have found that it is necessary to improve the vibration damping performance for the improvement of the comfortability of the ride. Herein, the vibration damping performance means the performance aiming at reducing vibrations of the frequency band (mode) of 20-50 Hz (vibrations in which a passenger feels shaking with passenger's feet or the like). The inventors have found that vertical vibrations of the front header which are caused by vertical vibrations of the windshield are one factor of that.
While it may be expected that the structures disclosed in the above-described patent documents could provide some effects in suppressing the vertical vibrations of the front header caused by the vertical vibrations of the windshield, more researches have been required to improve the comfortability of the ride.